Apparatus for producing a molded skin product

ABSTRACT

A process and an apparatus for producing a molded skin product such as an interior decoration member like an instrument panel for an automobile or other vehicle. The process includes charging a desired amount of synthetic resin powder into a treating container disposed facing a predetermined shaped molding mold surface. The mold surface is heated to a temperature of at least the melting temperature of the synthetic resin. The powder is spattered onto the mold surface by violently agitating the same by an agitation means whereby a fused coating of the powder is formed on the mold surface. The spattering is discontinued when the coating reaches a predetermined thickness. The mold surface is cooled thereby solidifying the coating to form the molded skin material. The molded skin material is then removed from the mold surface. The powder can be fluidized during the spattering. The apparatus includes the treating chamber for receiving a charge of synthetic resin powder, a metallic mold forming with the treating chamber a closed chamber with the mold having a mold surface facing the treating chamber, equipment for selectively heating and cooling the mold surface, and an agitation mechanism in the treating chamber for violently agitating the synthetic resin powder to spatter the same upwardly against the mold surface. The mold can be moveable from a closed position forming the closed chamber to an open position with the mold surface facing upwardly. The agitation mechanism includes at least one shaft and agitation blades mounted thereon.

This application is a divisional application of Ser. No. 494,103 filedMay 12, 1983, now U.S. Pat No. 4,552,715.

BACKGROUND OF THE INVENTION

This invention relates to a manufacturing process and a manufacturingapparatus of a molded skin material used for an interior decorationmember for a vehicle such as a motorcar or the like.

Molded skin materials used for an automobile or other vehicle interiordecoration member such as an instrument panel, a door panel and so on,generally have a complicated curved surface. Additionally, suchmaterials can have any desired pattern thereon such as seams, specificformed wrinkles or the like. A conventional manufacturing processcomprises charging a plastic sol into a mold having a predeterminedcurved shape and/or a pattern. An alternative previous method is knownas slush molding. Plastic powder is coated on a predetermined shapedmolding mold surface by electrodeposition coating and the coating isthen fused by heating so that a film thereof is formed thereon. Theformer process is defective in that air is liable to be confined to thecontact surface between the charged liquid and the mold, therebyproducing bubbles or voids and pinholes are liable to be created in themolded film due to the air included in the liquid. The latter process isdefective in that, because the powder is coated on the surface after itis charged with electricity, the flowing rate and the flowing amount ofthe powder from a gun are limited, resulting in lowering the coatingefficiency. This is especially so when a comparatively large-sized andcomplicated molded product is to be manufactured. The problem is that itis difficult to coat on every sideward and rearward part of the curvedmold surface. Therefore, it is inevitable for this process to provide amultiple head type gun apparatus wherein a large number of guns aredisposed at various necessary angles in relation to the molded surface.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a process forproduction of a molded skin material in which air bubbles, voids, andpinholes are avoided in the final molded skin material.

It is another object of the present invention to provide a process forproducing a molded skin material which is uniform in thickness.

It is yet another object of the present invention to provide a processfor producing a molded skin material which is highly efficient andsimple to conduct.

It is a further object of the present invention to provide an apparatuswhich is simple and efficient for producing a molded skin material.

It is a still further object of the present invention to provide anapparatus for producing a molded skin material which reduces thepossibilities of air bubbles, voids or pinholes in the final product.

It is a yet further object of the present invention to provide anapparatus for producing a molded skin material in which the finalproduct has uniform thickness.

These and other objects are obtained in a process for producing a moldedskin material wherein a desired amount of synthetic resin powder ischarged into a treating container disposed facing a predetermined shapedmolding mold surface. The mold surface is heated to a temperature of atleast the melting temperature of the synthetic resin. The powder isspattered onto the mold surface by violently agitating the same by anagitation means whereby a fused coating of the powder is formed on themold surface. The spattering is discontinued when the coating reaches apredetermined thickness. The mold surface is then cooled therebysolidifying the coating to form the molded skin material. The moldedskin material is thereafter removed from the mold surface. During thespattering, the powder can be fluidized.

The apparatus of the present invention comprises a treating containerhaving a lower portion with a space therein for receiving a charge ofsynthetic resin powder and metallic mold forming with the treatingcontainer a closed chamber, means for selectively heating and cooling amold surface of the mold which faces the treating container, andagitation means in the treating container for violently agitating thesynthetic resin powder. The agitation means spatters the powder upwardlyagainst the mold surface. The mold is moveable from a closed positionforming a closed chamber with the treating container and an openposition with the mold surface facing upwardly. The agitation means caninclude at least one shaft and agitation blades mounted thereon.

The at least one shaft can be mounted horizontally and can carry thereona plurality of agitation blades disposed axially at predeterminedintervals therealong. The agitation means can further comprise means forrotationally driving the at least one shaft selectively in eitherdirection.

The agitation means can comprise a plurality of shafts, each with alurality of blades thereon and means for rotationally driving each ofthe plurality of shafts selectively in either direction. A means formoving the at least one shaft axially can be provided. Furtherr, a meansfor tilting the at least one shaft relative to the molding surface canbe provided. The apparatus can further comprise means associated withthe lower portion of the treating container for fluidizing the syntheticresin powder therein.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and the attendant advantages of the presentinvention will become readily apparent by reference to the followingdetailed description when considered in conjunction with theaccompanying drawings wherein:

FIG. 1 is a side view, partly in section, of one example of thisinvention apparatus.

FIG. 2 is a side view of another embodying example thereof.

DETAILED DESCRIPTION OF THE INVENTION

Embodying examples of this invention will now be explained withreference to the accompanying drawings:

Referring to FIG. 1 showing one example thereof, a machine base 1 isfixedly provided with a treating container 2 thereon which has apredetermined depth and is open at its upper surface. A lower portionspace 3 of the container 2 is charged with synthetic resin powder whichcomprises a large number of fine particles a in the range of 30-200μ inparticle diameter. A rotary agitator 4 is horizontally provided in thislower portion space 3 including the charged layer of synthetic resinpowder. More in detail, a rotary shaft 4a thereof is placed horizontallywith both end portions thereof supported through bearings on mutuallyopposite side walls of the treating container 2. The shaft 4a hasagitation blade means thereon which comprises a number of agitationgroups each comprising radially extending agitation blades 4b. Theagitation groups are disposed on the shaft 4a at predetermined intervalsalong the axial direction thereof. At least one such agitator 4, andusually plural ones thereof are provided side by side, that is, inparallel one with another. An agitation motor 5 is connected to them.Means are provided for reversing rotation direction of the variousshafts. A bottom wall of the treating container 2 is composed of anair-permeable wall 6 such as an air filter or the like havinginnumerable fine holes and made of glass, fabric or the like. An airchamber 7 is provided below the wall 6. The chamber 7 is so arrangedthat compressed air may be introduced thereinto through an air supplyopening 8 made in the side wall of the chamber 7 and an air supply pipe9 connected to the opening 8. In this manner, the foregoing syntheticresin layer may be fluidized or brought into a floating condition by thesupplied air passing through the bottom wall 6. A meshed window 7a isprovided for air discharging. The upper surface of the treatingcontainer 2 is provided with a metallic mold 10 covering, that is,closing the same. The metallic mold 10 is provided with a downwardlydirected molding mold surface 11 having a predetermined complicatedcurved molding shape and additionally, as an occasion demands, a wrinklepattern or the like formed thereon. There is provided on the rearsurface of the molding mold surface 11 a temperature adjusting jacket 12into which a heating medium and a cooling medium may be introducedalternately for effecting heating and cooling, alternately, of the wholearea of the surface 11. The jacket 12 is selectively connected throughtwo communication openings 12a, 12a to a circuit 13 for the heatingmedium and a circuit 14 for the cooling medium. More in detail, thecircuit 13 for the heating medium such as oil, water or the like,includes a tank 15, a pump 16, a heater 17, a three-way valve 18 on oneside, and a three-way valve 19 on the other side, is connected throughthe foregoing communication openings 12a, 12a to the foregoing jacket 12for circulation supply of the heating medium. The circuit 14 for thecooling medium such as oil, water or the like, includes a tank 20, apump 21, a cooler 22, the foregoing three-way valve 19 and an additionalthree-way valve 23, and is connected through the foregoing communicationopenings 12a, 12a to the foregoing jacket 12 for circulation supply ofthe cooling medium.

For heating the temperature adjusting jacket 12, the heating medium fromthe tank 15 is pumped into the jacket 12 via the pump 16, heater 17,three-way valve 18 and a communication opeining 12a of the jacket 12,and flows out of the jacket 12 via the other communication opening 12aand the three-way valve 19 to the tank 15 to complete the cycle ofcirculation of the heating medium, during which time the circuit 14 forcirculation of the cooling medium is closed off from communication withthe jacket 12 by three-way valve 23 while the cooling medium circuit 14is maintained in closed circulation. For cooling the jacket 12, thecooling medium circuit 14 operates in similar manner, and the coolingmedium is pumped into the jacket 12 via the pump 21, three-way valve 23and a communication opening 12a of the jacket 12, and flows out of thejacket 12 via the other communication opening 12a and the three-wayvalve 19 through the cooler 22 to the tank 20 to complete the cycle ofcirculation of the cooling medium, during which time the heating mediumcircuit 13 is closed off from communication with the jacket 12 by thethree-way valve 18 while the heating medium circuit 13 is maintained inclosed circulation.

A circuit connecting between the cooler 22 and the three-way valve 23can serve for heightening the cooling or heating efficiency. Namely,when the metallic mold 10 is to be changed from heating to cooling, ifthe hot oil in the mold 10 is returned to the tank 20 for the coolingmedium, the efficiency becomes bad. Acccordingly, the foregoing circuitis used in this case for returning the hot oil to the tank 15 for theheating medium, and immediately thereafter the circuit is changed overto the cooling cycle. This is similarly applicable to the case that thecircuit is changed over from the cooling cycle to the heating cycle.

The metallic mold 10 is so arranged that, by turning of an opening andclosing mechanism 24 attached to the side surface thereof, the same canbe turned over to an open position wherein the molding mold surface 11thereof is directed upwards as shown by chain lines, so that after thecompletion of the molding operation, the molding mold surface 11 of themold 10 may be directed upwards and thereby taking out of the produce Amay be facilitated. It is preferrable that an air-tight sealing member25 such as a packing or the like is provided on the periphery of themolding mold surface 11 of the metallic mold 10.

Next, a manufacturing process of this invention using the foregoingexample of this invention apparatus will be explained as follows:

A desired amount of synthetic resin powder a is charged into thetreating container 2, and the metallic mold 10 is turned to close thetreating container 2 by turning the opening and closing mechanism 24.Under this condition, the air chamber 7 at the bottom portion of thetreating container 2 is supplied with air. The air flows thereintothrough the bottom wall 6 so as to fluidize the charged layer ofsynthetic resin into its flowing and floating condition. In themeanwhile, the jacket 12 of the metallic mold 10 is supplied with theheating medium such as oil or the like heated to a temperature above themelting point of the synthetic resin powder a. In this manner, themolding mold surface 11 thereof is heated to a predeterminedtemperature. Under this condition, the agitator 4 is driven to rotate sothat the large number of the disposed blade 4b groups are rotatedviolently at a high speed. The floating synthetic resin powder layer isdriven by the blades 46 to continuously, upwardly spatter. By thisoperation, the fine particles of the synthetic resin powder a are forcedto impinge strongly against the surface of the heated molding moldsurface 11 directed downwardly and located over the floating resinpowder and are fused on the surface 11 by the heat thereof. As a result,there is obtained a fused and firmly deposited layer of the syntheticresin powder without any air being confined between the same and themolding mold surface 11. Similarly, in sequence, fine particles of thesynthetic resin powder are forcedly accumulated on and are fused to theforegoing heated fused resin layer. If upward spattering of the resinpowder by the agitator is continued for 30-120 seconds, there isproduced a sheet of fused and molded resin coat of about 0.5-2 mms inthickness.

If the rotation of the agitator is reversed in the midst of theoperation and accordingly the rotation of the agitation blades arereversed, the direction of the spattered resin powder toward the moldsurface 11 is varied and a uniform and accurate layer forming inconformity with the curved shape of the mold surface can be ensured. Itis preferrable that the regular rotation and the reverse rotation of theagitator are repeated 2-3 times. It is further preferrable that theuniform coating property is more improved by such a manner that one ofthe two agitators, for instance, disposed in parallel one with anotheris rotated in regular direction while the remaining one is rotated inthe reverse direction so as to create a turbulent flow of powder. Whenthe thickness of the resin layer reaches a desired amount, the rotationof the agitator and the supply of the air are stopped, and the fusedresin layer is kept at a predetermined temperature in order to ensure auniform film forming treatment thereof. Thereafter, the supply of theheating medium into the jacket 12 is stopped, and the predeterminedthree-way valves are changed over to the cooling circuit side, wherebythe cooling medium is supplied into the jacket 12 to cool the moldingmold surface 11 for solidifying the resin layer. Thus, the molded skinmaterial A of the predetermined thickness may be produced.

Thereafter, the opening and closing mechanism 24 is operated, andthereby the metallic mold 10 is turned over so that the molding moldsurface 11 is opened, and accordingly the molded product A is turned toface upwardly. As a result, the product A can be easily taken out. Theagitator 4 can be arranged so that the same may be shifted left or rightto a predetermined position in the axial direction of the shaft and/orarranged so that the shaft 4a thereof may be inclined in relation to themold surface 11, whereby a uniform adhesion of the synthetic resinpowder to the molding mold surface is more improved.

If the metallic mold 10 which is turnable through the opening andclosing mechanism 24 is provided on each of both sides of the treatmentcontainer 2 as shown in FIG. 2, a manufacturing procedure becomespossible wherein while one of the metallic molds 10, 10 is positioned onthe upper surface of the container 2 for closing the same and themolding mold surface 11 thereof is heated to form thereon a fused moldedfilm, the other thereof is turned over and the fused molded coatpreviously formed thereon is solidified by cooling and is taken outtherefrom. This procedure can be repeated alternately, so that it isadvantageous in that a number of the skin material products A can bemanufactured continuously and at a high efficiency.

Concrete Example

Vinyl chloride resin powder which is in a range of about 30-200μ inparticle diameter, and, for instance, is 150μ in average particlediameter alone, or a powder of a composition composed of 100 partsthereof, 70-80 parts of a plasticizer, 1-5 parts of a stabilizer, 1-5parts of a pigment and 1-2 parts of an additive is used as the rawmaterial. The metallic mold is previously heated to a temperature of230° C.

The foregoing raw material powder is brought into a fluidized conditionby the inflow of air and is agitated and spattered on the mold surfacefor 60 seconds by the agitator being repeatedly turned in a regulardirection and in the reverse direction alternately at a rotation speedof 1200 r.p.m. so that a uniformly fused layer of the powder is formed.Thereafter, the alternate turning of the agitator is stopped and thesupply of the air is also stopped. The metallic mold is kept at atemperature of 230° C. for 120 seconds, whereby the fused resin layer isso matured on the mold surface as to be smooth in surface and uniform inthickness. Thereafter, the metallic mold is cooled, and the temperaturethereof is lowered to 80° C. in 120 seconds, whereby the fused resincoat is solidified and thus the manufacturing thereof is completed.Consequently, there is obtained a predetermined form of mold skinmaterial which has a uniform thickness of about 1.2 mms and is composedsolely or chiefly of vinyl chloride and has at its surface a wrinklepattern.

In a case where the foregoing vinyl chloride skin material produced bythis invention is used as the raw material for manufacturing an interiordecoration member for a vehicle such as a motorcar or the like, theprocess for instance, can include separately preparing a core sheetmember of ABS resin by a conventional process, setting the core in oneof two molds facing one another, setting the product of the presentinvention set in the other thereof, charging the urethane foam liquidbetween the two. The foam is then cured and an interior decorationmember having at its surface this invention skin material layer isproduced.

Thus, according to this invention, the synthetic resin powder charged inthe treating container is violently spattered, impinged, and fused onthe whole area of the heated molding mold surface, so that a goodquality of molded skin material is formed accurately according to theshape of the predetermined shaped molding surface. This product is freefrom air bubbles, voids, and pinholes and can be produced in a shorttime. The productivity thereof can be improved.

It is readily apparent that the above-described method and apparatusmeets all of the objects mentioned above and also has the advantage ofwide commerical utility. It should be understood that the specific formof the invention hereinabove described is intended to be representativeonly, as certain modifications within the scope of these teachings willbe apparent to those skilled in the art.

Accordingly, reference should be made to the following claims indetermining the full scope of the invention.

What is claimed is:
 1. An apparatus for producing a molded skin materialcomprising:a treating container having a lower portion provided with aspace therein for receiving a charge of synthetic resin powder, ametallic mold forming with said treating container a closed chamber,said mold having a molding mold surface facing said treating container,said mold being movable to and from a closed position with said moldsurface facing downwardly for forming with said treating container saidclosed chamber and an open position with said mold surface facingupwardly, means for selectively heating and cooling said mold surface,and agitation means provided in said treating container for violentlyagitating the synthetic resin powder charged in said treating containerto spatter the same upwardly against said mold surface, said agitationmeans including at least one shaft having agitation blades mountedthereon.
 2. The apparatus of claim 1, wherein said at least one shaft ismounted horizontally and carries thereon a plurality of agitation bladesdisposed at predetermined axial intervals therealong.
 3. The apparatusof claim 2 wherein said agitation means further includes means forrotationally driving said at least one shaft selectively in eitherdirection.
 4. The apparatus of claim 1 wherein said agitation meanscomprises a plurality of shafts each with a plurality of blades thereonand means for rotationally driving each of said plurality of shaftsselectively in either direction.
 5. The apparatus of claim 1 furthercomprising means for moving said at least one shaft axially.
 6. Theapparatus of claim 2 further comprising means for moving said at leastone shaft axially.
 7. The apparatus of claim 1 further comprising meansfor tilting said at least one shaft relative to said molding surface. 8.The apparatus of claim 2 further comprising means for tilting said atleast one shaft relative to said molding surface.
 9. The apparatus ofclaim 3 further comprising means for tilting said at least one shaftrelative to said molding surface.
 10. The apparatus of claim 1 furthercomprising means associated with said lower portion of said treatingcontainer for fluidizing said synthetic resin powder therein.
 11. Theapparatus of claim 1, wherein said movable metallic mold is madeturnable between said closed and open positions thereof through anopening and closing mechanism provided on a side of said treatingcontainer.
 12. The apparatus of claim 1, wherein a pair of said movablemetallic molds are provided, each said mold being made turnable betweensaid closed and open positions thereof through a corresponding one of apair of opening and closing mechanisms provided on respective sides ofsaid treating container.
 13. The apparatus of claim 1, wherein saidmeans for selectively heating and cooling said mold surface comprises atemperature adjusting jacket provided on a rear surface of said metallicmold into which a heating medium and a cooling medium may be introducedalternately for effecting heating and cooling, alternately, of theentire mold surface.
 14. The apparatus of claim 13, wherein said meansfor selectively heating and cooling said mold surface further comprisesat least two communication openings in said temperature adjusting jacketwhich may be selectively placed in communication with a circuit for saidheating medium and a circuit for said cooling medium.
 15. The apparatusof claim 1, wherein said means for selectively heating and cooling saidmold surface comprise:a temperature adjusting jacket provided on a rearsurface of said metallic mold into which a heating medium and a coolingmedium may be introduced alternately for effecting heating and cooling,alternately, of the whole area of said mold surface; heating circuitmeans for heating and circulating said heating medium; cooling circuitmeans for cooling and circulating said cooling medium; at least twocommunication openings provided in said temperature adjusting jacket incommunication therewith; and means for selectively communicating saidheating circuit means and said cooling circuit means with saidcommunication openings.
 16. The apparatus of claim 15, wherein saidheating circuit means includes a first tank, a first pump incommunication with said first tank, a heater in communication with saidfirst pump, a first three-way valve in communication with said heaterand selectively communicable with one of said communication openings andsaid first tank, and a second three-way valve in communication withanother of said communication openings and selectively communicable withsaid first tank;and wherein said cooling circuit means includes a secondtank, a second pump in communication with said second tank, a thirdthree-way valve in communication with said second pump and selectivelycommunicable with said one of said communication openings and a cooler,said cooler being in communication also with said second tank, and saidsecond three-way valve in communication with said other of saidcommunication openings and selectively communicable with said cooler.17. The apparatus of claim 15, further comprising circuit meansconnecting between said cooler and said third three-way valve forheightening the heating and cooling efficiency of said means forselectively heating and cooling said mold surface.